Roads of Arabia

02bis (08) Arabie US p54-69_BAT.qxd 23/06/10 19:38 Page 68
ROADS OF ARABIA
(preceding pages)
Bare ruiniform rock formations rise above
a sandy plain that provides moderate grazing for camels
(al-Ula region, Hijaz)
Lakes were formed then, the sediments of which can be found under the sands of Nafud
and the Rub al-Khali. At al-Mudawwara, in the south of Jordan, lake deposits have been
dated with 230 Th/234 U 2 to the last Interglacial period (between 120,000 and 85,000
years BP). The sands carried by the big wadis coming down from granitic or sandstone massifs
accumulated in the depressions. During the dry phases, sands were picked up by the
winds, producing the ergs of Nafud and Rub al-Khali. It was in these periods that the great
deep aquifers found in the sedimentary formations in the north-west of the peninsula and
even more in the eastern regions and under Rub al-Khali, sometimes several thousand
metres deep and often more or less associated with oil deposits. But these aquifers are mostly
fossil and today are over-exploited.
The great climatic changes of the Quaternary were also manifested by important variations
of the sea level. In the last glacial period the sea level fell approximately 120 metres. The
Arabian Gulf at the time was entirely dewatered, the common estuary of the Tigris and the
Euphrates then being on the edge of the Gulf of Oman, human settlement was possible. At the
end of the glacial age the Gulf was gradually replenished in water, but complex movements of
isostatic compensation occurred, causing more or less significant modifications of the shoreline.
The humid periods offered prehistoric man very different living conditions from the
ones humans have today, as vegetation was far more developed and there were more watering
points.
2. U/TH: technique for dating carbonate materials
based on the thorium (230Th)-uranium (234U)
ratio, uranium 234 naturally decaying into thorium
230.
Bibliography:
Fisher and Membery 1998; Fleitmann, Burns,
Mangini et al. 2007; Jado and Zötl 1984; Lézine,
Saliège, Robert et al. 1998; Petit-Maire, Carbonel,
Reyss, Sanlaville, Abed, Bourrouilh, Fontugne and
Yasin 2010 (in press); Sanlaville 2000; Al-Sayari
and Zötl 1978.
Conclusion
The Arabian Peninsula confronts man with particularly challenging conditions: the extent
and massiveness; often hostile landscape, steep mountains and high plateaus broken by deep
gorges, immense and unwelcoming dune fields; dangerous navigation in the bordering seas
due to winds and currents, the presence of coral reefs and sandy or silty shallows; a harsh
climate, intense heat, considerable temperature contrasts and, above all, great aridity and
the serious problem of water supply.
Nevertheless, men were able to settle and live there from very early on thanks to a certain
number of favourable conditions. Certain regions were probably more viable than others:
the coasts with resources for fishing and shell gathering, the high zones in the west and
their foothills, the areas benefiting from karstic springs.
The peninsula opens widely to the north towards Syria and Iraq while the three bordering
seas facilitate connections with the outside world. The Arabian Gulf enjoys an excellent
position, between Mesopotamia and Oman and between Arabia and Iran and, through the
Strait of Hormuz, possibilities of relations and exchanges with Asia and Africa via the Indian
Ocean. Thanks to the Bab al-Mandeb and the Isthmus of Suez, contacts and exchanges with
Africa were possible and established early. Moreover, men were able to find raw materials
for making their tools: flint, quartzite, volcanic materials (obsidian, andesite, basalt) and
subsequently mining resources like copper and iron, or plant resources such as incense and
myrrh. Itineraries were set up and the domestication of donkeys and camels allowed the
increase of travel and trade.
The existence of lush, more or less extensive oases is made possible by springs (al-Ula region, Hijaz)
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